# Relationship history for MSHA mine 4503819

Current hierarchy: **Pamp Gary  Maiers; Pamp Matthew  Maiers → Central Washington Asphalt → Screen Plant #1**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Central Washington Asphalt → Screen Plant #1; 2021-04-26 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Pamp Gary  Maiers et al → Screen Plant #1; 2021-04-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Pamp Gary  Maiers et al → Central Washington Asphalt; 2021-04-26 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Pamp Matthew  Maiers et al → Central Washington Asphalt; 2021-04-26 to current/open; source msha-controller-operator-history